Phospholipase C catalyzes the hydrolysis of the sn-3 phosphate head group in phospholipids including phosphatidylcholine, phosphatidyletanolamine, and phosphatidylserine, resulting in the formation of 1,2-diacylglycerol and water soluble phosphate esters (e.g., phosphorylcholine, phosphorylethanolamine, and phosphorylserine). Because of this activity phospholipase C can be used for refining vegetable oils such as soybean oil.
Phospholipase C can be used to process vegetable oils, e.g., vegetable oils intended for human consumption or biodiesel production such as soybean, corn, canola, rapeseed, and sunflower oil. In many cases, degumming is the first step in the refining of crude oil. In enzymatic degumming, phospholipase C is added to crude oil, and the mixture is heated in the presence of water. Under these conditions, phospholipase C hydrolyses the major oil phospholipids, e.g., phosphatidylcholine and phosphatidylethanolamine. The resulting esters, e.g., phosphorylcholine and phosphorylethanolamine, are soluble in water and separated from the oil, e.g., by centrifugation. 1,2-diacylglycerol, which is also formed during the hydrolysis, remains in the oil phase. The residual phospholipase C can be removed from the oil during subsequent purification steps, e.g., by repeatedly washing of the oil with hot water, bleaching, and deodorization.